The effects of ligands of cannabinoid CB1 receptors (agonist HU-210 and antagonist SR 141716A) on some behavioral reactions in an experimental model of depression – bilateral olfactory bulbectomy (OBX) have been studied.

The results showed modulating effects of HU-210 и SR 141716A on the depressive-like state in ОВХ rats (exploratory and locomotor activity, anxiety, nociception, learning and memory). Upon 7 day i.c.v. administration of the substances in the right lateral ventricle of OBX rats for a period of 7 days it was observed that HU-210 decreased locomotor activity and improved the habituation (which could be interpreted as an antidepressive effect), showed anxiolytic-like and antinociceptive effects and improved learning and memory, while SR 141716A increased locomotor activity and anxiety, decreased the pain threshold and impaired learning and memory. The experiments with chronic oral administration Rimonabant (SR 141716A ) for 14 days before and after OBX showed that the treatment in the period before OBX did not affect the behavior of OBX rats, while after OBX augmented the depressive-like state, induced by the bulbectomy.

The results reveal an involvement of CB1 receptors in the development of the depressive-like state.